A self-centering anti-jamming hydraulic valve spool and a hydraulic valve

Abstract

A self-centering anti-jamming hydraulic valve spool and a hydraulic valve belong to the technical field of hydraulic valves. The hydraulic valve spool includes a valve spool and a thin-walled structure sleeved on the valve spool. An annular groove is formed on the inner side wall of the thin-walled structure. A hydraulic oil flow channel is formed inside the valve spool. The inlet end of the hydraulic oil flow channel is arranged on the end face of the valve spool, and the outlet end of the hydraulic oil flow channel communicates with the annular groove. Hydraulic oil flows into the annular groove through the hydraulic oil flow channel, thereby changing the hydraulic pressure drop distribution of the valve spool in the hydraulic valve to achieve self-centering of the valve spool. The hydraulic valve spool of the present invention consists of only two parts and has a simple structure. There is no need to machine concentric pressure equalizing grooves or add auxiliary devices to avoid jamming. The micro-deformation of the valve spool is realized by the high-pressure action of hydraulic oil, thereby realizing self-centering and improving the processing efficiency. Moreover, no matter which side of the valve spool is connected to high pressure, the conical effect is achieved, which can improve the assembly efficiency. By utilizing the characteristic that the conical shape is beneficial to self-centering, the working accuracy and reliability of the valve spool are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydraulic valves, and particularly relates to a self-centering anti-clamping hydraulic valve core and a hydraulic valve. Background Art

[0002] Gap seals are usually adopted between the valve body and the valve core of a hydraulic valve. Since gap seals have advantages such as small friction, less heat generation, long service life, and compact structure, and the sealing gap magnitude is extremely small, a high requirement is imposed on the surface machining accuracy of parts. Therefore, it is often applied to hydraulic valves with small sizes and high working precision requirements. The working performance of a hydraulic valve depends on the flow state of the hydraulic oil in the sealing gap and the working state of the valve body. When the hydraulic valve is working, the valve core reciprocates in the cavity, and there is a pressure difference on both sides of the valve core. Due to the existence of the sealing gap, oil leakage cannot be completely avoided. However, when the oil leakage is serious, it will cause energy loss, the movement speed of the valve core will be affected, the working efficiency of the hydraulic valve will be reduced, and in serious cases, it will affect the normal operation of the hydraulic system. Therefore, the sealing gap magnitude is usually very small, and a high requirement is imposed on the machining accuracy of the valve core. Due to reasons such as irregular machining, local burrs, and non-concentric equalizing grooves of the valve core, the valve core will be subjected to a radial unbalanced force, resulting in the valve core being eccentric, thereby increasing the friction between the valve core and the hydraulic oil and reducing the movement speed of the valve core. In serious cases, the valve core will be in direct contact with the valve body, resulting in valve core clamping.

[0003] The main reason for hydraulic clamping is caused by the radial unbalanced force generated by the geometric shape error and coaxiality error of the valve core. When the valve core is conical due to machining errors and the large end of the cone faces the high-pressure end, it is called reverse cone. Also, due to assembly errors, when the axis of the valve core is parallel but not coaxial with the axis of the valve body hole, eccentricity occurs, and the pressure drops of the hydraulic oil at the upper and lower parts of the valve core are different, generating a radial unbalanced force, which makes the eccentricity distance increase until hydraulic clamping occurs. When the small end of the cone faces the high-pressure end, it is called forward cone. When the forward cone is eccentric, it is subjected to a radial unbalanced force, and the eccentricity distance becomes smaller and smaller, playing a role of self-centering. Summary of the Invention

[0004] In order to solve the problem of hydraulic clamping of hydraulic valves, the present invention further provides a self-centering anti-clamping hydraulic valve core and a hydraulic valve with simple structure, good stability, high working precision, and convenient processing.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A self-centering anti-clamping hydraulic valve core includes a valve core and a thin-walled structure sleeved on the valve core. An annular groove is formed on the inner side wall of the thin-walled structure. A hydraulic oil flow channel is formed inside the valve core. The inlet end of the hydraulic oil flow channel is arranged on the end face of the valve core, and the outlet end of the hydraulic oil flow channel is communicated with the annular groove. The hydraulic oil flows into the annular groove through the hydraulic oil flow channel, thereby changing the hydraulic pressure drop distribution of the valve core in the hydraulic valve to achieve self-centering of the valve core.

[0007] A hydraulic valve comprises a valve body, a connecting rod, a hydraulic spring, a push rod and the hydraulic valve core according to any one of claims 1 to 3; three hydraulic valve cores are arranged at equal intervals along the axis of the connecting rod and fixed on the connecting rod, the hydraulic spring is fixed on the right side of the connecting rod, and plays a role in buffering, shock absorption and compensation, the push rod is fixed on the left side of the connecting rod, and the connecting rod is coaxially installed in the valve body, and there is a nanometer-level sealing gap between the inner wall of the valve body and the outer wall of the hydraulic valve core.

[0008] Compared with the prior art, the present invention has the following beneficial effects:

[0009] 1. The hydraulic valve core of the present invention consists of only two parts, the valve core and the thin-wall structure, and has a simple structure. There is no need to process concentric pressure-equalizing grooves or add external auxiliary devices to avoid clamping. The high pressure of the hydraulic oil is used to achieve micro-deformation of the valve core, thereby changing the size of the sealing gap and the distribution of the hydraulic pressure drop. The radial unbalanced force applied to the valve core with processing errors when it acts as a reverse cone can reduce the eccentricity and achieve self-centering; the radial unbalanced force applied to the valve core when it acts as a forward cone can further reduce the eccentricity, accelerate the self-centering process, and improve processing efficiency; and the forward cone effect can be achieved regardless of which side of the valve core is passed through high pressure, which can improve assembly efficiency; the self-centering feature of the forward cone is utilized to improve the working accuracy and reliability of the valve core.

[0010] 2. In order to ensure the normal operation of the hydraulic valve, in addition to improving the valve core processing accuracy as much as possible, a number of pressure-equalizing grooves concentric with the valve core are opened on the valve core surface along the axial direction. This requires high processing accuracy and low processing efficiency. The present invention can achieve self-centering of the valve core through simple assembly of a simple valve core and a thin-walled structure, without the need to process pressure-equalizing grooves, thereby improving processing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the hydraulic valve core structure of the present invention;

[0012] Figure 2 This is a schematic diagram of the eccentric reverse cone force direction of the hydraulic valve core of the present invention;

[0013] Figure 3 This is a schematic diagram of the force direction of the eccentric cone of the hydraulic valve core of the present invention;

[0014] Figure 4 This is a schematic diagram of the axial cross-sectional structure of the hydraulic valve of the present invention;

[0015] Figure 5 This is the distribution diagram of the radial unbalanced hydraulic pressure of the original valve core eccentric reverse cone;

[0016] Figure 6 This is the radial unbalanced hydraulic pressure distribution diagram of the eccentric reverse cone valve core of the present invention;

[0017] Figure 7 is the distribution diagram of the radial unbalanced hydraulic pressure of the original valve core with eccentric and tapered shape;

[0018] Figure 8 is the distribution diagram of the radial unbalanced hydraulic pressure of the valve core with eccentric and tapered shape of the present invention;

[0019] Wherein: 1. Thin-walled structure; 2. Annular groove A; 3. Hydraulic oil flow channel A; 4. Valve core; 5. Annular groove B; 6. Hydraulic oil flow channel B; 7. Valve body; 8. Connecting rod; 9. Hydraulic spring; 10. Oil chamber A; 11. Oil chamber B; 12. Oil chamber C; 13. Oil chamber D; 14. Oil chamber E; 15. Push rod. Specific embodiments

[0020] In order to better understand the purpose, structure and function of the present invention, the following further detailed description of the present invention will be made in conjunction with the accompanying drawings.

[0021] Refer to Figure 1 As shown, a self-centering anti-clamping hydraulic valve core of the present invention includes a valve core 4 and a thin-walled structure 1 cold-fitted on the valve core 4. The thin-walled structure 1 is a cylindrical structure. An annular groove is provided on the inner side wall of the thin-walled structure 1. The valve core 4 is a cylindrical structure. A hydraulic oil flow channel is provided inside the valve core 4. The inlet end of the hydraulic oil flow channel is arranged on the end face of the valve core 4, and the outlet end of the hydraulic oil flow channel communicates with the annular groove, and the hydraulic oil flows into the annular groove through the hydraulic oil flow channel, so as to change the hydraulic pressure drop distribution of the valve core 4 in the hydraulic valve, so as to realize the self-centering of the valve core 4.

[0022] Two centrally symmetric annular grooves are provided on the inner side wall of the thin-walled structure 1, namely the front and rear annular groove A2 and annular groove B5, and the annular groove A2 and annular groove B5 have the same structural dimensions.

[0023] Two centrally symmetric hydraulic oil flow channels are provided inside the valve core 4, namely the hydraulic oil flow channel A3 with the inlet facing backward and the hydraulic oil flow channel B6 with the inlet facing forward. The inlet end of the hydraulic oil flow channel A3 communicates with the rear end face of the valve core 4, and the outlet end of the hydraulic oil flow channel A3 communicates with the annular groove A2 arranged at the front end. The inlet end of the hydraulic oil flow channel B6 communicates with the front end face of the valve core 4, and the outlet end of the hydraulic oil flow channel B6 communicates with the annular groove B5 arranged at the rear end. By flowing the hydraulic oil into the hydraulic oil flow channel B6 or the hydraulic oil flow channel A3, the radial resultant force received by the valve core 4 is changed, so as to change the size of the local sealing gap between the valve core 4 and the hydraulic valve, and change the hydraulic pressure drop distribution, so as to realize the self-centering of the valve core 4.

[0024] Under the action of hydraulic oil, the thin-walled structure 1 at the annular groove A2 or the annular groove B5 can bulge locally under high pressure, thereby changing the size of the local sealing gap between the spool 4 and the hydraulic valve, changing the hydraulic pressure drop distribution, so as to realize the self-centering of the spool 4.

[0025] The schematic diagram of the force direction of the eccentric inverse cone of this hydraulic spool is as Figure 2 shown. The pressure distribution diagrams of the eccentric inverse cone of the spool before and after improvement during operation are as Figure 5 、 Figure 6 shown. The spool 4 is conical due to processing errors, and the large end of the cone faces the high-pressure part, which is called an inverse cone. When the axis of the spool 4 is parallel to but not coaxial with the axis of the valve body 7 hole, that is, there is eccentricity, resulting in different sizes of the upper and lower sealing gaps of the spool 4, different hydraulic pressure drops, and a radial unbalanced force is generated. When the axis of the spool 4 is on the upper side of the axis of the valve body 7 hole, the pressure drop degree of the upper part of the spool 4 is greater than that of the lower part, causing the spool 4 to be subjected to a radial resultant force F upward, resulting in an increasing eccentricity; at the same time, the hydraulic oil flows into the annular groove B5 through the hydraulic oil flow channel B6, and the thin-walled structure 1 near the annular groove B5 bulges locally under the action of high-pressure oil, changing the size of the local sealing gap, that is, changing the hydraulic pressure drop distribution, and the generated radial resultant force F' is downward, reducing the eccentricity between the valve body 7 and the spool 4, and realizing the self-centering of the spool 4.

[0026] The schematic diagram of the force direction of the eccentric forward cone of this hydraulic spool is as Figure 3 shown. The pressure distribution diagrams of the eccentric forward cone of the spool before and after improvement during operation are as Figure 7 、 Figure 8 shown. The spool 4 is conical due to processing errors, and the small end of the cone faces the high-pressure part, which is called a forward cone. When the axis of the spool 4 is parallel to but not coaxial with the axis of the valve body 7 hole, that is, there is eccentricity, resulting in different sizes of the upper and lower sealing gaps of the spool 4, different hydraulic pressure drops, and a radial unbalanced force is generated. When the axis of the spool 4 is on the upper side of the axis of the valve body 7 hole, the pressure drop degree of the upper part of the spool 4 is less than that of the lower part, causing the spool 4 to be subjected to a radial resultant force F downward, reducing the eccentricity; at the same time, the hydraulic oil flows into the annular groove B5 through the hydraulic oil flow channel B6, and the thin-walled structure 1 near the annular groove B5 bulges locally under the action of high-pressure oil, changing the size of the local sealing gap, that is, changing the hydraulic pressure drop distribution, and the generated radial resultant force F' is downward, further reducing the eccentricity between the valve body 7 and the spool 4, and accelerating the self-centering process of the spool 4.

[0027] The hydraulic spool is applied to a hydraulic control valve, taking a directional control valve as an example.

[0028] Refer to Figure 4, a hydraulic valve of the present invention includes a valve body 7, a connecting rod 8, a hydraulic spring 9, a push rod 15, and the hydraulic valve core described in any one of claims 1-3; three hydraulic valve cores are arranged at equal intervals along the axis of the connecting rod 8 and are cold-mounted and fixed on the connecting rod 8. The hydraulic spring 9 is fixed on the right side of the connecting rod 8 to play a role in buffering, shock absorption and compensation. The push rod 15 is fixed on the left side of the connecting rod 8. The connecting rod 8 is coaxially installed in the valve body 7 and uses clearance sealing. There is a nanoscale sealing gap between the inner side wall of the valve body 7 and the outer side wall of the hydraulic valve core.

[0029] A plurality of hydraulic oil flow channels C are opened in the valve body 7. The interfaces of the plurality of hydraulic oil flow channels C include a working oil inlet A, a working oil return port B, an oil inlet P, and an oil return port T. The working oil inlet A and the working oil return port B are connected to both ends of the actuator, i.e., the hydraulic cylinder. The oil return port T is connected to the oil tank, and the oil inlet P is connected to the hydraulic pump. A through hole is opened in the valve body 7 to install the connecting rod 8 and the hydraulic valve core. The sealing method uses clearance sealing, and oil cavities A10, B11, C12, D13, and E14 are opened on the through hole. The oil cavity A10 is connected to the oil tank through the oil return interface T. The oil cavity B11 is connected to the rodless cavity of the hydraulic cylinder through the working oil return port B. The oil cavity C12 is connected to the hydraulic pump through the oil inlet P. The oil cavity D13 is connected to the rod cavity of the hydraulic cylinder through the working oil inlet A. The oil cavity E14 and the oil cavity A10 are connected through one of the hydraulic oil flow channels C opened on the valve body 7.

[0030] The push rod 15 is connected with an electromagnet. When the electromagnet is energized, it attracts and pushes the hydraulic valve core to move to the right, so that the working oil inlet A and the oil inlet P are connected, and the working oil return port B and the oil return port T are connected, so that the hydraulic oil in the hydraulic pump flows into the rod cavity of the hydraulic cylinder, and the hydraulic oil in the rodless cavity flows back to the oil tank; when the push rod 15 is pushed for electrode commutation, at this time, when the electromagnet is energized, it attracts and makes the hydraulic valve core move to the left, so that the working oil return port B and the oil inlet P are connected, and the working oil inlet A and the oil return port T are connected, so that the hydraulic oil in the hydraulic pump flows into the rodless cavity of the hydraulic cylinder, and the hydraulic oil in the rod cavity flows back to the oil tank, thereby realizing the reciprocating motion of the actuator, i.e., the hydraulic cylinder. And during this process, the hydraulic valve core can achieve self-centering through the hydraulic oil flow channel B6 and the annular groove B5.

[0031] Specifically: when the electromagnet is energized, the hydraulic valve core moves to the right, the rod chamber is filled with oil, the oil chamber is filled with oil, the oil chamber D13 communicates with the oil chamber C12 and is filled with high-pressure oil, the oil chamber B11 communicates with the oil chamber A10 and is filled with low-pressure oil, and the hydraulic valve core operates in an environment with a pressure difference at both ends and the oil pressure on the left side is higher than that on the right side. At this time, due to machining errors, the geometric shape of the hydraulic valve core is conical, and at the same time, assembly errors result in the non-coaxial assembly of the hydraulic valve core and the valve body 7, causing eccentricity, so that the sealing gaps on both sides of the hydraulic valve core are different in size, resulting in different degrees of hydraulic pressure drop. The ordinary structure will ultimately lead to different degrees of hydraulic pressure drop on both sides of the hydraulic valve core, causing the radial force on the hydraulic valve core to be unbalanced, resulting in an increase in the eccentricity distance, an increase in the movement resistance of the hydraulic valve core, and jamming in severe cases; at the same time, the hydraulic oil flows into the annular groove B5 through the hydraulic oil flow channel B6, and under the action of the high-pressure oil, the thin-walled structure 1 near the annular groove B5 bulges locally under high pressure, changing the local sealing gap size, that is, changing the hydraulic pressure drop distribution, and the resulting radial resultant force reduces the eccentricity distance. The self-centering of the hydraulic valve core is realized, ensuring the normal operation of the hydraulic valve.

[0032] When the push rod 15 changes direction and the electromagnet is energized, the hydraulic valve core moves to the left, the rodless chamber is filled with oil, the oil chamber is filled with oil, the oil chamber D13 communicates with the oil chamber E14 and the oil chamber A10 and is filled with low-pressure oil, the oil chamber B11 communicates with the oil chamber C12 and is filled with high-pressure oil, and the hydraulic valve core operates in an environment with a pressure difference at both ends and the oil pressure on the right side is higher than that on the left side. At this time, due to machining errors, the geometric shape of the hydraulic valve core is conical, and at the same time, assembly errors result in the non-coaxial assembly of the hydraulic valve core and the valve body 7, causing eccentricity, so that the sealing gaps on both sides of the hydraulic valve core are different in size, resulting in different degrees of hydraulic pressure drop. The ordinary structure will ultimately lead to different degrees of hydraulic pressure drop on both sides of the hydraulic valve core, causing the radial force on the hydraulic valve core to be unbalanced, resulting in an increase in the eccentricity distance, an increase in the movement resistance of the hydraulic valve core, and jamming in severe cases; at the same time, the hydraulic oil flows into the annular groove A2 through the hydraulic oil flow channel A3, and under the action of the high-pressure oil, the thin-walled structure 1 near the annular groove A2 bulges locally under high pressure, changing the local sealing gap size, that is, changing the hydraulic pressure drop distribution, and the resulting radial resultant force reduces the eccentricity distance. The self-centering of the hydraulic valve core is realized, ensuring the normal operation of the hydraulic valve.

[0033] It can be understood that the present invention is described through some embodiments. Those skilled in the art know that without departing from the spirit and scope of the present invention, various changes or equivalent replacements can be made to these features and embodiments. In addition, under the teaching of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application belong to the scope protected by the present invention.

Claims

1. A self-centering anti-jamming hydraulic valve core, characterized in that: It includes a valve core (4) and a thin-walled structure (1) sleeved on the valve core (4). An annular groove is formed on the inner side wall of the thin-walled structure (1). A hydraulic oil flow channel is formed inside the valve core (4). The inlet end of the hydraulic oil flow channel is arranged on the end face of the valve core (4), and the outlet end of the hydraulic oil flow channel communicates with the annular groove. Hydraulic oil flows into the annular groove through the hydraulic oil flow channel, thereby changing the hydraulic pressure drop distribution of the valve core (4) in the hydraulic valve to achieve self-centering of the valve core (4). Two centrally symmetric annular grooves are arranged on the inner side wall of the thin-walled structure (1), namely an annular groove A (2) and an annular groove B (5) arranged front and back. The annular groove A (2) and the annular groove B (5) have the same structural dimensions. Two centrally symmetric hydraulic oil flow channels are formed inside the valve core (4), namely a hydraulic oil flow channel A (3) with the inlet facing backward and a hydraulic oil flow channel B (6) with the inlet facing forward. The inlet end of the hydraulic oil flow channel A (3) communicates with the rear end face of the valve core (4), and the outlet end of the hydraulic oil flow channel A (3) communicates with the annular groove A (2) arranged at the front end. The inlet end of the hydraulic oil flow channel B (6) communicates with the front end face of the valve core (4), and the outlet end of the hydraulic oil flow channel B (6) communicates with the annular groove B (5) arranged at the rear end. By flowing hydraulic oil into the hydraulic oil flow channel B (6) or the hydraulic oil flow channel A (3), the radial resultant force received by the valve core (4) is changed, thereby changing the size of the local sealing gap between the valve core (4) and the hydraulic valve and changing the hydraulic pressure drop distribution to achieve self-centering of the valve core (4).

2. The self-centering anti-jamming hydraulic valve core according to claim 1, characterized in that: Under the action of hydraulic oil, the thin-walled structure (1) at the annular groove A (2) or the annular groove B (5) can undergo local high-pressure bulging, thereby changing the size of the local sealing gap between the valve core (4) and the hydraulic valve and changing the hydraulic pressure drop distribution to achieve self-centering of the valve core (4).

3. A hydraulic valve, characterized in that: It includes a valve body (7), a connecting rod (8), a hydraulic spring (9), a push rod (15) and the hydraulic valve core according to any one of claims 1-2. Three hydraulic valve cores are arranged at equal intervals along the axis of the connecting rod (8) and fixed on the connecting rod (8). The hydraulic spring (9) is fixed on the right side of the connecting rod (8) to play a role in buffering, shock absorption and compensation. The push rod (15) is fixed on the left side of the connecting rod (8). The connecting rod (8) is coaxially installed in the valve body (7), and there is a nanoscale sealing gap between the inner side wall of the valve body (7) and the outer side wall of the hydraulic valve core.

4. A hydraulic valve according to claim 3, characterized in that: A plurality of hydraulic oil flow channels C are formed in the valve body (7). The interfaces of the plurality of hydraulic oil flow channels C include a working oil inlet A, a working oil return port B, an oil inlet P, and an oil return port T. A through hole is formed in the valve body (7) to install a connecting rod (8) and a hydraulic valve core, and oil chambers A (10), B (11), C (12), D (13), and E (14) are formed in the through hole. The oil chamber A (10) is connected to a fuel tank through an oil return interface T. The oil chamber B (11) is connected to the rodless chamber of a hydraulic cylinder through the working oil return port B. The oil chamber C (12) is connected to a hydraulic pump through the oil inlet P. The oil chamber D (13) is connected to the rod chamber of the hydraulic cylinder through the working oil inlet A. The oil chamber E (14) and the oil chamber A (10) are communicated through one of the hydraulic oil flow channels C formed in the valve body (7).

5. A hydraulic valve according to claim 4, characterized in that: The push rod (15) is connected with an electromagnet. When the electromagnet is energized, it attracts and pushes the hydraulic valve core to move to the right, so that the working oil inlet A and the oil inlet P are communicated, and the working oil return port B and the oil return port T are communicated, enabling the hydraulic oil in the hydraulic pump to flow into the rod chamber of the hydraulic cylinder, and the hydraulic oil in the rodless chamber to flow back to the fuel tank; when the push rod (15) is pushed for electrode commutation, at this time, when the electromagnet is energized, it attracts and makes the hydraulic valve core move to the left, so that the working oil return port B and the oil inlet P are communicated, and the working oil inlet A and the oil return port T are communicated, enabling the hydraulic oil in the hydraulic pump to flow into the rodless chamber of the hydraulic cylinder, and the hydraulic oil in the rod chamber to flow back to the fuel tank, thereby realizing the reciprocating motion of the actuator, i.e., the hydraulic cylinder, and during this process, the hydraulic valve core can achieve self-centering through the hydraulic oil flow channel B (6) and the annular groove B (5).

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